Network hub for a reconfigurable data network having physical transmission media

ABSTRACT

A data network includes a plurality of network devices, a plurality of physical. transmission lines each coupled to a respective one of said plurality of network devices, and a network hub coupled to each of said plurality of physical transmission lines. The network hub has a removable and replaceable termination element providing signal connectivity between selected ones of said plurality of transmission lines. In one embodiment, the data network is installed within an aircraft including a fuselage, an empennage connected to the fuselage, a lift-generating surface coupled to the fuselage, and at least one engine for propelling the aircraft.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates generally to communication networks and,in particular, to data networks having physical transmission media.Still more particularly, the present invention is directed to aremovable and replaceable network hub that facilitates centralizedtesting and reconfiguration of a data network having physicaltransmission media.

2. Description of the Related Art

A data network requires ongoing maintenance to upgrade or replace agingor failed network devices and to insert additional network devices intothe data communication network. Such maintenance is performed relativelyeasily when the network device(s) to be replaced, upgraded or insertedare installed within a special purpose facility, such as a computer roomhaving raised-access flooring or a network closet. In such cases, theease of maintenance is due to the ability to easily access both thenetwork devices and the physical transmission media (e.g., cabling)utilized to connect the network devices to the data communicationnetwork.

In some network installations, however, network maintenance isproblematical in that the devices and/or the network transmission mediacomprising the data network are not easily accessible. For example, theinsertion or removal of a network device or other topological changes toa data network installed within an aircraft often requires gutting thecockpit and/or cabin of the aircraft in order to access the installationsites of one or more network devices and portions of the aircraft wiringaffected by the network change.

FIG. 1 is a high level plan view of an aircraft having a conventionaldata network. As illustrated, aircraft 10, which comprises a fuselage12, wings 14, engines 16 and tail section (empennage) 18, has a datanetwork 20 installed therein. In the depicted embodiment, data network20 is a fibre channel arbitrated loop including a number of networkdevices 22, which are coupled together by fiber optic cables 24terminated on either end by connectors 26. Network devices 22 mayinclude, for example, an avionics computer, avionics sensors, aircraftsystem controls, and communications equipment.

As will be appreciated, data network 20 is typically installed withinfuselage 12 behind cockpit instrumentation panels and other fixtureswithin the cabin interior. Consequently, if data network 20 requirestesting, maintenance, or modification, for example, by the addition orremoval of a network device 22 or reordering of network devices 22within the loop, many of the fixtures of the cabin interior may have tobe removed to access network devices 22 and/or fiber optic cables 24. Itis therefore time consuming, expensive and inconvenient to reconfigureor test data network 20 and its components.

SUMMARY OF THE INVENTION

In recognition of the foregoing and additional difficulties with testingand reconfiguring conventional data network installations, the presentinvention provides an improved data network and a network hub forstructures such as aircraft in which access to network infrastructure isrestricted.

In accordance with the present invention, the data network includes aplurality of network devices, a plurality of physical transmission lineseach coupled to a respective one of said plurality of network devices,and a network hub coupled to each of said plurality of physicaltransmission lines. The network hub has a removable and replaceabletermination element providing signal connectivity between selected onesof said plurality of transmission lines. In one embodiment, the datanetwork is installed within an aircraft including a fuselage, anempennage connected to the fuselage, a lift-generating surface coupledto the fuselage, and at is least one engine for propelling the aircraft.

Additional objects, features, and advantages of the present inventionwill become apparent from the following detailed written description.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself however, as well as apreferred mode of use, further objects and advantages thereof, will bestbe understood by reference to the following detailed description of anillustrative embodiment when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a high level plan view of an aircraft having a conventionaldata network installed therein;

FIG. 2 is a high level plan view of an aircraft having a data networkinstalled therein in accordance with the present invention; and

FIG. 3 depicts an exploded view of an exemplary embodiment of a fiberoptic network hub in accordance with the present invention.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT

With reference again to the figures and in particular to FIG. 2, thereis depicted a high level plan view of an aircraft that, in accordancewith the present invention, has a data network installed therein thatfacilitates network testing, maintenance and reconfiguration. As shown,aircraft 30, which in the, illustrated embodiment is a commercial ormilitary transport aircraft, includes a number of conventionalcomponents, including a fuselage 12, a tail section (empennage) 18, apair of wings 14 providing lift, and a number of engines 16 to propelaircraft 30. As will become apparent, the present invention is notlimited to the illustrated aircraft embodiment, but is insteadapplicable to any type of aircraft, including combat aircraft,surveillance aircraft, helicopters, etc., which incorporates a datanetwork.

As shown, aircraft 30 has a data network 32 installed therein. In thedepicted embodiment, data network 32 is a fibre channel arbitrated loopincluding a number of network devices 22 distributed throughout fuselage12 (and in other embodiments, within wings 14 and/or empennage 18). At aphysical level, network devices 22 are coupled together in a starconfiguration in which each network device 22, which may comprise anavionics computer, avionics sensor, aircraft system control,communications equipment or other network-compatible device, isconnected to a first end of a respective fiber optic cable 24 by aconnector 26, and each fiber optic cable 24 has a second end connectedto fiber optic hub 40. As described further below with respect to FIG.3, fiber optic hub 40 provides signal connectivity between selectedfiber optic cables 24 so that data network 32 logically functions as anarbitrated loop network, despite its star-configuration physicaltopology.

Although in most cases it is preferable to couple all network devices 22to a single fiber optic hub 40 as shown in FIG. 2A, it is contemplatedthat, in some embodiments, it may be preferable for redundancy ormodularity to implement multiple fiber optic hubs 40 coupled together byone or more fiber optic cables. In such embodiments, appropriateimplementation of fiber optic hubs 40 will still permit the logicalconfiguration of the data network as a single loop.

Referring now to FIG. 3, there is illustrated an exploded elevation viewof an exemplary embodiment of a fiber optic network hub 40 in accordancewith the present invention. As shown, fiber optic network hub 40, whichis preferably installed behind a removable panel accessible from thecabin interior or on the exterior of fuselage 12, comprises a connector44 and a removable and replaceable cap 46.

Connector 44, which may comprise, for example, a. MIL-C-38999 connector,provides connections for a number of fiber optic cables 24 comprisingthe aircraft's fiber optic harness 42. Connector 44 may be connected toreplaceable cap 46 by applying manual mating force to connector 44 andreplaceable cap 46 in the directions indicated by arrows 50 and 52, andmaybe disconnected from replaceable cap 46 by applying manual force toconnector 44 and replaceable cap 46 in directions opposite to arrows 50and 52, respectively.

Replaceable cap 46 includes a housing 47 containing jumpers 48 that eachprovide optical signal connectivity between one or more fiber opticcables 24. For example, in order to couple network devices 22 in alogical loop having a desired ordering of network devices 22, jumper 48a may provide signal connectivity between fiber optic cables 24 a and 24b. As should thus be apparent to those skilled in the art, networkdevices 22 may be reconfigured in a logical loop having any arbitraryordering of network devices 22 (or even into another network topology)by installing a replaceable cap 46 containing jumpers 48 providing theappropriate signal connections between fiber optic cables 24.Consequently, network reconfiguration can advantageously be accomplishedwithout the need to access network devices 22 or fiber optic cables 24.

Network equipment modifications and testing are also simplified by theimplementation of fiber optic hub 40 within data network 32. Forexample, if a network device 22 is to be added to or removed from datanetwork 32, only network hub 40, the installation location of thenetwork device 22, and the cabling between the installation location andnetwork hub 40 need to be accessed. Unlike updates to prior art network20 of FIG. 1, updates to data network 30 do not require access to othernetwork devices 22 and the fiber optic cables 24 to which they areconnected. Network testing is similarly simplified by the implementationof fiber optic hub 40 within data network 32 in that there is no need totear down the cabin interior to access a test site within data network32. Instead, the removable panel covering fiber optic hub 40 (e.g., inthe cabin interior or-on the exterior of fuselage 12) can be removed topermit each fiber optic cable 24 and network device 22 to beindividually probed and/or accessed for testing purposes.

For fiber optic networks, the star configuration topology enabled byfiber optic hub 40 also provides performance advantages. In particular,the use of fiber optic hub 40 within data network 32 of FIG. 2 reducesthe number of connections, thus reducing fiber optic power loss.

As has been described, the present invention provides a network hub anda data network for an aircraft (or similar structure) that facilitatesnetwork reconfiguration and testing without rewiring and/or extensivephysical access to the network infrastructure. According to the presentinvention, the data network includes a plurality of network devices eachcoupled by a respective one of a plurality of physical transmissionlines to a network hub. The network hub includes a connector coupled tothe physical transmission lines and a removable termination element(e.g., replaceable cap 46) providing signal connectivity betweenselected transmission lines.

While the invention has been particularly shown and described withreference to a preferred embodiment, it will be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention.For example, although the present invention has been described withreference to an illustrative embodiment employing fiber optic cabling,it should be understood that the present invention is also applicable tonetworks utilizing other physical network transmission media, such asconventional metal wiring.

What is claimed is:
 1. An aircraft comprising: a body; and a datanetwork within said body, said data network including: a plurality ofnetwork devices spaced apart from one another and distributed atmultiple locations within said aircraft; a plurality of cables eachcoupled to a respective one of said plurality of network devices by arespective one of a plurality of first connectors; and a network hubwithin said body and spaced apart from each of said plurality of networkdevices, said network hub including a second connector coupled to eachof sail plurality of cables, said network hub further including aremovable and replaceable termination element that mates with saidsecond connector to provide signal connectivity between selected ones ofsaid plurality of cables, wherein said removable and replaceabletermination element couples each of said plurality of cables to anotherof said plurality of cables such that any signal transmitted on saidplurality of cables by said plurality of network devices both enters andexits said network hub at said second connector.
 2. The aircraft ofclaim 1, wherein said plurality of cables comprises a plurality of fiberoptic cables.
 3. The aircraft of claim 1, wherein said plurality ofcables includes at least three cables.
 4. The aircraft of claim 1,wherein said network hub is disposed adjacent an exterior of the body,and wherein said body includes an openable and closeable exterior accesspanel covering said network hub to permit access to said network hubfrom the exterior of said body.
 5. The aircraft of claim 1, wherein:said body includes: an empennage; and a lift-generating surface; andsaid aircraft further comprises at least one engine for propelling theaircraft, said at least one engine being coupled to at least one of thebody and the lift-generating surface.
 6. The aircraft of claim 1,wherein said replaceable termination element comprises a firstreplaceable termination element and wherein said aircraft furthercomprises a diverse second replaceable termination element that mateswith said second connector to provide signal connectivity betweendifferent ones of said plurality of cables wherein said first and saidsecond replaceable termination elements can be alternatively mated withsaid second connector to obtain diverse first and second networkconfigurations of said data network, respectively.
 7. The aircraft ofclaim 1, wherein: said plurality of network devices comprises a firstplurality of network devices; said plurality of cables comprises a firstplurality of cables; said network hub comprises a first network hub; andsaid data network further comprises: a second plurality of networkdevices; a second plurality of cables each coupled to a respective oneof said second plurality of network devices; a second network hubcoupled to said second plurality of cables, said second network hubincluding a removable and replaceable termination element providingsignal connectivity between selected ones of said second plurality ofcables; and a hub cable coupling said first and second network hubs toprovide signal connectivity between at least one of said first pluralityof network devices and one of said second plurality of network devices.8. The aircraft of claim 1, wherein: said plurality of network devicesare physically connected by said plurality of cables to said secondconnector of said network hub in a star configuration; and saidremovable and replaceable termination element of said network hubprovides signal connectivity between selected ones of said plurality ofcables such that said plurality of network devices communicate signalswith one another in a logical loop.
 9. The aircraft of claim 1, whereinsaid removable and replaceable termination element is generallyL-shaped.
 10. An aircraft, comprising: a body; and a data network withinsaid body, said data network including: a plurality of network devicesspaced apart from one another and distributed at multiple locationswithin said aircraft; a plurality of cables each coupled to a respectiveone of said plurality of network devices by a respective one of a firstplurality of first connectors; and a network hub means within said bodyand spaced apart from each of said plurality of network devices, saidnetwork hub means including a second connector coupled to each of saidplurality of cables, said network hub means having a removable andreplaceable termination element means for providing signal connectivitybetween selected ones of said plurality of cables such that each of saidplurality of cables is coupled to another of said plurality of cablesand any signal transmitted on said plurality of cables by said pluralityof network devices both enters and exits said network hub at said secondconnector.